1. Field of the Invention
Apparatuses and methods consistent with the present invention relate an Analog to Digital (AD) conversion. More particularly, the present invention relates to a parallel AD converter for converting an analog signal to a digital signal using a Micro Electro Mechanical Systems (MEMS) technology, and an AD converting method.
2. Description of the Related Art
Many natural signals change in an analog (continuous) manner as time passes. To understand the phenomena of nature, it is required to measure the magnitude of the analog signals over time. The measured values may be processed and analyzed using computers, and to do so, a device is required to convert the observed analog signal to a digital value processable by the computer. This device is an Analog-to-Digital (AD) converter.
An AD converter may be one of several different types, including, e.g., a parallel comparator type, a single-slop type, a dual-slope type, a successive approximation type, and the like. A parallel comparator type AD converter uses an OP amplifier as the comparator, and outputs a digital value, e.g., a binary code output, by encoding the output signal of the comparator, which, when an input voltage is higher than a reference voltage, outputs a voltage corresponding to the logical value ‘1’.
A parallel comparator type AD converter may include a plurality of resistors for setting the various reference voltages, a plurality of comparators for comparing the input voltage with each of the reference voltages, and an encoder for outputting a digital signal.
However, when the AD converter includes the multiple resistances and the multiple comparators, the resistances and the comparators consume a large amount of power. Also, to achieve higher resolution and/or higher speed, more resistors and comparators may be required, which causes even greater power consumption. Specifically, to implement an n-bit AD converter, at least 2n-ary resistors and (2n−1)-ary comparators may be required. As the number of output bits of the AD converter increases, the power consumption increases exponentially.
Therefore, what is needed is an AD converter for achieving high resolution and/or high speed with lower power consumption.